The present invention relates generally to the structure of an umbrella of the type normally used to protect persons against weather conditions. In the general construction of umbrellas of the type to which the present invention relates, a stick or main umbrella shaft has attached at one end thereof a handle which carries at its other end a hub from which ribs of a generally flexible material extend in a radial direction from the axis of the umbrella stick or main shaft. The ribs are circumferentially distributed about the hub of the umbrella and they are pivotally supported thereby at the end of the stick. A slider mechanism which is movable longitudinally on the stick may be operated to open and close the canopy of the umbrella which is attached to the ribs. The slider mechanism has attached thereto stays which are linked between the slider and the ribs whereby the ribs may be moved from a position extending generally parallel to the umbrella stick when the umbrella is closed to a position outstanding radially from the stick to open the umbrella and to extend the canopy thereof.
This type of umbrella design conforms generally to conventional approaches to the manufacture of an umbrella where all of the ribs are of the same length thereby resulting in an umbrella canopy which has a generally circular peripheral configuration. That is, the area which may be covered by such an umbrella when in use generally comprises a circular pattern.
Umbrellas of this conventional type are usually adequate only to protect a single person. When such umbrellas are utilized by two persons together, the available surface of the umbrella canopy is not large enough for a covering sufficient to protect both people so that only a generally insufficient protection from one side of each individual may be produced. When two persons walk side by side it becomes disadvantageous with regard to the protective covering provided by conventional umbrellas even if each person carries a separate umbrella. Even with separate umbrellas, there will be a mutual interference by the lateral overhang of the umbrellas and during a particularly heavy rain water running off from one umbrella will be deflected in the direction of the person walking adjacent to the person carrying the one umbrella.
Attempts have been made to overcome problems arising with regard to covering a plurality of persons walking together during inclement weather. One attempt has involved eliminating the circular peripheral configuration of the umbrella canopy and substituting an elliptical or oblong shaped canopy. Such a structure is known from German Pat. Nos. 29,894 and 447,684. However, in designs of this type, the umbrella ribs must of necessity be made of unequal lengths. In order to facilitate opening and closing of the umbrella without interference with the operation thereof, the longer umbrella ribs must be made longitudinally variable in their lengths and this is accomplished by a design which enables a telescopic type of expansion and contraction of the ribs.
Such a structure, however, not only increases the expense involved in manufacturing the umbrella but it necessarily also involves a rather clumsy folding of the umbrella canopy inasmuch as, because of the unequal lengths of the ribs, the canopy material covering the longer ribs will involve excess material thereby causing a cumbersome folding of the canopy. This not only involves undesired wear of the canopy material but it also produces an unattractive appearance in the folded umbrella. For this reason, it is generally recommended and emphasized that a sheath or covering be used for the folded umbrella, as indicated in German Pat. No. 29,894.
Accordingly, it will be found that with the present state of the art, it would be desirable to provide an umbrella structure wherein the overall area covered by the umbrella may be enlarged without requiring that the ribs of the umbrella be made of unequal lengths and without requiring a telescoping type of umbrella rib.